The cranial base in obstructive sleep apnea

Purpose: The purpose of this investigation was to determine if there are cranial base differences in adults with obstructive sleep apnea (without identifiable craniofacial abnormalities) when compared with those of adults without airway problems. Methods: Cephalometric analysis of the cranial base of 52 patients with documented sleep apnea were compared with 96 normal adult patients. Each of the groups was subdivided based on skeletal profiles (Class I, II, III). Cephalometric measurements included cranial base flexure angle and anterior and posterior cranial base lengths. Standard analysis of variance and Students' t test were used to determine level of significance. Results: The cranial base flexure angle in patients with documented sleep apnea was significantly more acute than that found in the nonapnea group. Patients with a skeletal Class III profile had the most acute cranial base flexure whereas those with Class II profiles had the most obtuse angles. This pattern was true for apnea and nonapnea groups. No cranial base length differences could be found in either group. Conclusion: The results of this study demonstrate that there were abnormalities of the cranial base in patients with obstructive sleep apnea. Abnormalities of the cranial base seen in "nonsyndrome" obstructive sleep apnea patients are similar to those seen in patients with certain identifiable syndromes. This may suggest that sleep apnea is a reflection of a form of craniofacial syndrome.